1. Field of the Invention
The present invention is broadly concerned with a new cleaning composition that can be used for household or industrial cleaning purposes. The composition can be in powder form, in an aqueous solution, or in the form of a tablet.
2. Description of the Prior Art
Relatively mild general purpose cleaners have long been sought for purposes such as household cleaners, grease cutters, and hard-surface cleaners. Previously, many such cleaners relied on harsh alkaline sources such as alkali metal and alkaline earth metal hydroxides to reduce critical micelle concentration, neutralize acids, stabilize solid soil suspensions, and solubilize water-insoluble materials. While effective, these cleaners were highly caustic, and as such, were difficult and dangerous to use. Milder cleaners were developed using less caustic bases as alkalinity sources, but these were only effective for limited uses because of their decreased cleaning efficiency and grease-cutting properties.
Many detergents consisting of alkaline carbonates, anionic and nonionic surfactants, and sequestrants have been described previously. Anionic surfactants include compounds such as alkyl carboxylates, alkyl sulfates, and alkyl benzene sulfonates, and are useful for removing oily soils and stains. Some anionic surfactants significantly increase the foaming of detergent formulations. This problem is sometimes addressed by the addition of defoaming agents, but many of these compounds, such as silicones, oils, fats, and waxes, add expense and bulk to cleaning products. Nonionic surfactants generally improve rinse properties of cleaning compounds and include compounds such as linear alcohol ethoxylates, nonyl phenol ethoxylates, and other polyoxyalkylene compounds. Cleaners containing nonyl phenol ethoxylates have only limited uses, as they are inappropriate for cleaning surfaces that come in contact with food items.
Sequestrants are included to bind water hardness-causing ions to improve the cleaning action of detergents. Common examples include chelating agents such as EDTA, NTA, and organic phosphates such as phosphonic acids, sodium tripolyphosphate, and tetrapotassium phosphate. EDTA may be harmful to the environment because it is not readily biodegradable. Inorganic phosphates have recently been shown to be harmful to the environment.
Cleaners in the form of rapidly dissolving pre-measured tablets or pellets are also desirable. Such formulations eliminate uncertainty associated with measuring liquids or powders, and reduce the necessity of handling cleaning compositions. Producing pre-measured pellets or tablets using high concentrations of sodium carbonate have presented some problems, as they tend to absorb water and swell and crack over time. This problem has been addressed by using anhydrous alkaline carbonates to reduce the large amounts of water in cleaning tablets.
There is a need for relatively mild cleaners with good grease cutting capabilities and increased cleaning efficiency. These cleaners should also be stable, and have long shelf lives.